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A DISCOURSE

i. It is afserted, that tlie larger parts of these rings are on the south and-sunny side of the tree, (which is very rational and probable,) insomuch*.,that by cutting a tree transverse, and drawing a diameter through thebroadest and narrowest parts of the rings,, a meridian line may be de-scribed.

The outer spaces are generally narrower than the inner, not only In,their narrower sides, but also on their broader, compared with the samesides of the inner ; notwithstanding which, they are for the most, part, ifnot altogether, bigger upon the whole account.

Of these spaces, the outer extremities, in Fir, and the like woods, that:have them larger and grofser, are more dense, hard, and compact; theinner more soft and spongy ; by, which difference of substance it is, that ;the rings themselves come to be distinguished..

According as the bodies and boughs of trees, or several parts of the -same, are bigger or lefser,.so is the number, as well as the breadth of the'circular spaces, greater or left; and the like, according to the age*.,especially the number.

It-is commonly and'very, probably afserted, that a tree gains a newring every year. In. the body of a great Oak in the New-Forest, cuttransversely even (where many of the trees are accounted to be somehundreds of years old) three and.four hundred have been distinguished.In a Fir-tree, which is said to have just so many rows of boughs about;it as it is of years growth, there has been observed just one lefs im-mediately above one row, than immediately below, Hence some pro-bable account may be given of the difference between the outer and theinner parts of the rings,. that the outermost being newly produced in thesummer, the exterior superficies is condensed, in the. winter, „

In the young branches and twigs of trees there is a pith in the middle,-which in some, as Ash, and especially Elder, equals or exceeds in dimen-sions the rest, of the substance, but waxes lefs as they grow bigger, andin the great boughs and trunk scarce is to be found: This gives way forthe growth of the inward rings, which .at first were lefs than the outer,